Department of Health Official Gordon Kelly said, "It's just another indicator that is pretty pervasive in the county. It runs from one end to another and everything in between. We've had positives in the Mid-Valley, we've had positives in the Upper-Valley."

Transmission to humans is done through mosquito bites. Using mosquito repellent and removing standing water from your property are key steps to prevent mosquito bites.

For more information go to the official Department of Health website at www.doh.wa.gov/WNV.